1. Field of the Invention
The present invention is related to blood sampling techniques and devices and, more particularly, is directed towards a method and apparatus for substantially reducing the risk of contamination of handlers of a blood sampling syringe and needle by the sampled blood.
2. Description of the Prior Art
Blood gas aspiration is a technique widely practiced by nurses, physicians, medical students and respiratory therapists in order to obtain important data for proper management of an ill patient. For example, in patients suffering from diseases of the lungs or heart, it is important to know the oxygen content of the blood, which may be determined by blood gas analysis of arterial blood.
Such blood is obtained from the patient using a conventional hypodermic syringe. The use of a conventional needle and syringe in blood gas aspiration techniques unfortunately lends itself to possible serious contamination of the individual obtaining the blood by the patient's blood. This risk of contamination extends to those individuals, such as technicians or the like, who most subsequently handle the blood-filled syringe and/or needle during analysis.
There are several steps during the performance of the blood gas aspiration technique where the risk to the syringe handler of contamination by the patient's blood may be identified as greatest. One of those instances occurs in connection with the manual purging of air from the syringe which is required as a result of the inevitable aspiration of air into the syringe when the sample is being taken. It is quite important that air not be allowed to contaminate the blood sample, which would distort the results of the gas analysis. Therefore, as a practical matter, after the sample has been drawn, the taker of the sample generally must eject some blood through the needle prior to sending the sample-filled syringe to the laboratory to be analyzed, in order to purge all air from the sample. The amount of blood which is ejected during this purging process necessarily depends upon the skill and technique of the user. The practical result is, however, that a careless individual may undesirably expose his fingers, either directly or through a piece of gauze, to the ejected, possibly contaminated blood of the patient.
Immediately following the purging of air from the syringe as above-described, the open end of the needle of the syringe must be pushed into a small rubber stopper or the like preparatory to sending the sample-filled syringe to a laboratory for analysis. If a person is careless, there is a chance that the open end of the needle will touch or prick his fingers, thereby creating another opportunity for contamination.
As an alternative to pushing the needle into a stopper, the person sampling the blood may choose to remove the needle from the syringe altogether prior to sending the blood-filled syringe to the lab. In this procedure, after the needle is removed, the open end of the syringe must be plugged with a rubber syringe cap, and the proximity of the user's hands to the patient's blood sample is again perilously close.
Still another opportunity for contamination occurs after the laboratory technician receives the blood-filled syringe for analysis. The technician must either remove the stoppered needle, which is generally done by grasping the base of the needle assembly at a point adjacent the end of the blood-filled syringe, or, alternatively, the technician must manually remove the syringe cap, which also places his hands in close proximity to the blood. In either event, the chances of getting blood on his hands is great, which, obviously, increases the risk of contamination.
It is therefore apparent that there is a great need for some type of device and technique which can minimize or at least substantially reduce the risk of contamination from a diseased patient's blood for those individuals, from the person initially drawing the blood sample to the person doing the blood analysis, who must handle the blood-filled hypodermic syringe.